‡ Claims that adhesive is "acid-free", "photo safe" and/or "safe for use" are based upon (i) Satisfactory test results obtained from Photographic Activity Tests per ISO 14523 and non-acidic pH Tests per TAPPI 509; (ii) Certifications from material manufacturers; and (iii) Atomic scans of adhesive following removal of backing paper. Data from independent tests performed at the Image Permanence Institute at Rochester Institute of Technology.